TALLAHASSEE - A half-billion-dollar deal aimed at buying farmland in the Everglades to help the ailing ecosystem should be rejected because it serves no public purpose and will only delay restoration further, an attorney argued today before Florida's Supreme Court.

"Land purchases alone accomplish nothing," Dexter Lehtinen, a lawyer representing the Miccosukee Indians living in the Everglades, argued before the justices in Tallahassee.

Republican Gov. Charlie Crist wants the state to pay $536 million to U.S. Sugar Corp. for 73,000 acres of the company's holdings in the Everglades. Crist has called it a "once in a lifetime" opportunity to buy back key land long used in agricultural production.

The Miccosukee and U.S. Sugar's main rival, Florida Crystals, however, say the deal is a waste of taxpayer money.

They argue that the South Florida Water Management District, which oversees Everglades restoration, has no specific restoration plans in place for the land, which will only be bought, then leased back to U.S. Sugar at a nominal rate until construction projects are developed.

The state says it plans to build reservoirs and treatment marshes on the land to help restore some natural flow and clean pollutants from urban runoff and fertilizers in the water before it flows south into the remainder of the Everglades.

"As complicated and convoluted as the appellants want to make this case, it's very simple," argued water district attorney Randall Hanna. "What we're doing here is we're buying land for Everglades restoration."

The tribe and Florida Crystals want the court to reject a state bid to issue bonds to pay for the purchase. They argue that without specific plans for the land, any deal would pad the pockets of executives at the nation's largest cane sugar producer at the expense of taxpayers.

"Their plan is to buy the land and figure out what they're going to do with it later," argued Joseph Klock, an attorney representing U.S. Sugar rivals, who also claims the leaseback option in the deal will give its competitor an unfair advantage.

The justices peppered attorneys with questions about why the state must have more detailed plans for the land to consider the purchase a benefit to the public.

"How specific does the plan have to be? Do we have to have every detail outlined before we can say, 'Yes, you can begin to acquire this land?'" asked Chief Justice Peggy A. Quince.

Lehtinen argued that not enough specifics have been provided under Florida law.

"There is no proposed project," he said. "They commit to nothing."

The proposal has been supported by environmental groups as key to putting long-stalled restoration back on track.

"We believe this land acquisition provides the best and last chance for significant Everglades restoration," argued attorney E. Thom Rumberger on behalf of the Florida Audubon Society.

The Everglades have been dying for decades. Burgeoning farms and development have effectively drained and polluted much of the swamp, long dissected by dikes, dams and canals.

The state and federal governments' efforts to restore the wetlands have been stymied for years by funding shortfalls, legal challenges and political bickering.

The U.S. Sugar deal has already been cut by more than half from the initial plan announced in 2008, when Crist proposed buying out the company holdings altogether in a $1.75 billion purchase for all its 180,000 acres and assets.

Meanwhile, U.S. Sugar says it's done negotiating with the state. If this deal falls through, it's over.

"This deal is the deal," said company spokeswoman Judy Sanchez.